<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
</head>

<body>
  <div id="app">
    <h2>{{msg}}</h2>
    <button @click="msg = msg.split('').reverse().join('')">翻转世界</button>
  </div>
  <script>
    new Vue({
      el: '#app',
      data: {
        msg: 'Hello World'
      }
    })
  </script>
</body>

</html>